coreboot: Add nyan blaze chromebook configs

This adds coreboot configuration for the HP Chromebook 14 G3, which is
based on the "google/nyan_blaze" mainboard in upstream coreboot. It uses
the shared tree for the "nyan" baseboard.

The config is based on the following defconfig:

    # CONFIG_USE_BLOBS is not set
    CONFIG_VENDOR_GOOGLE=y
    CONFIG_CBFS_SIZE=0x400000
    CONFIG_BOOT_DEVICE_SPI_FLASH_BUS=4
    CONFIG_BOARD_GOOGLE_NYAN_BLAZE=y
    CONFIG_CONSOLE_CBMEM_BUFFER_SIZE=0x20000
    CONFIG_DRIVERS_AS3722_RTC_BUS=4
    CONFIG_DRIVERS_AS3722_RTC_ADDR=0x40
    CONFIG_UART_PCI_ADDR=0x0
    CONFIG_I2C_TRANSFER_TIMEOUT_US=500000

Untested since I don't have the nyan blaze chromebook.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>